Energy and Power problem (change in tempurature)

[madeeeeee]

Homework Statement

David is traveling in his car (1500 kg) at 72 km/h. He sees a dog on the road and hits the brakes, what is the final temperature of his brake pads if they have a combined mass of 10 kg, a heat capacity of 300 J/kgC and they start at 20 degrees Celsius?

Homework Equations

Q=mcT
Change in T=T2-T1

The Attempt at a Solution

I am wondering if i have done this right

Ek=1/2mv^2
= 1/2*1500kg*20m/s^2
=300000
-3.0x10^5 J

change in temperature =Q/mc
=3.0x10^5 J/10 kg*300 J/kgC
=100 degrees C
100+20=120 degress Celsius

120 is final temperature of break
-Is this correct?

 

[PhanthomJay]

Looks good! Some of the kinetic energy may be lost to sound, etc., but essentially, all of the kinetic energy is transformed to heat energy.

 

[madeeeeee]

Thank you!